The invention relates to a torque transmitting apparatus intended for coupling two misaligned shafts. More particular, the present invention relates to a non-constant velocity torque transmitting device or coupling although it will be understood by those skilled in the art that with various modifications the coupling in accordance with the invention could be a constant velocity joint. A very common example of such a torque transmitting device is the universal joint typically disposed at the axial extremities of an automobile drive shaft. Many other variable angle torque transmitting devices are known. If there is no misalignment of the shafts then it is easy to use flanges on the respective shafts that are bolted together.
Coupling apparatus which permits the tilting or transmission of torque between two shafts which are disposed at a fixed angle or a varying angle are also well known. In some case the requirement to transmit torque between angle shafts may occur because of space limitation. Apparatus of known types includes Cardan Joints which have two yokes which cooperate with a cross assembly. This is the construction commonly utilized for automobile universal joints.
Other well known designs are known as constant velocity joints because the input and output shafts maintain the same angular velocity through out each rotation of the respective shafts. Constant velocity joints are in general more complex and more expensive than joints which do not have this construction. The non-constant velocity joints are typically limited in operating speed because of the velocity fluctuation. The prior art non-constant joints include slipper couplings, ball joints, so called aircraft joints and ball and trunnion joints. Known constant velocity U-joints include Rzeppa, Tripot, Weiss and Tracta.
Still other known couplings shear couplings in which two facing plates are capped and joined with a resilient angular element shaped and constructed like an automobile tire. Other elastomeric flex members include so called rubber block constructions and flexible sleeve couplings which utilize two flanges with internal teeth that engaged a flexible sleeve with external teeth. Others include a rubber block construction and a compression construction. Flexible coupling constructions includes spring, Schmidt and silent chain constructions. Still other constructions utilize flexible disks, plastic chains and sliding disks. The prior art also includes the apparatus described in U.S. Pat. No. 3,081,114 which shows a cylindrical section shaped surface retained in a cylindrical section shaped cavity.
U.S. Pat. No. 1,143,571 shows a universal joint with a casing having a spherical socket. The socket receives a ribbed shaft extremity.
U.S. Pat. No. 2,109,935 shows a coupling having a driving member and a driven member each having recesses. Bearing blocks are disposed in the recesses and contact the outer surface of the other member to transmit power from one member to the other member.
U.S. Pat. No. 3,587,249 shows a universal joint with a driving ball mounted on a shaft which is received in a hemispherical shell. A projection on the driving ball enters a groove in the shell to permit a transmission of torque when the respective shafts are at angles with respect to each other.
The prior art apparatus in general has been much more complex than it is desirable and in many cases has been constructed in a manner that was relative large for a given amount of torque transmission. Some of these apparatus are very difficult to rebuild and thus must be replaced in their entirety and accordingly are relatively expensive.
As noted above, the non-constant angular velocity joints are limited with respect to the speed at which they can be operated because of the effects of angular velocity changes. Many of the earlier apparatus are also severely limited with respect to the angles which can be tolerated between the respective shafts.
It is an object of the invention to provide an angular torque transmission joint that is relatively small in size with relatively high torque transmitting capability and which will be suitable for use on automobile tilt steering columns as well as other torque transmission couplings such as between motors and pumps, drive shafts for automobiles and other applications.
It is yet another object to the invention to provide a joint that may be easily manufactured.